The invention relates to apparatus for open end friction spinning of the type which includes two adjacently arranged friction rollers driven in the same direction and forming a yarn forming wedge slot, which rollers respectively exhibit a shell, which in the region of both of its ends is carried by roller bearings.
In an apparatus for open end friction spinning of the above mentioned general kind (DE-OS No. 31 41 733), it is known to use roller bearings to carry the shell of the rollers in the region of both of the ends. In this manner, the accuracy of the disposition of the two shells with respect to one another is improved as compared to a flying arrangement. In the known construction, in which the shells are formed as hyperboloids, the ends of the shells are provided with sliding type intermediate pieces which are formed as receptacles for the outer ring of the roller bearing. As to the kind of drive for the rollers, there is nothing described.
The invention is based upon the problem to so form the drive and the bearing for rollers in an apparatus of the above-mentioned kind, that while maintaining a high accuracy, a simple design and also a simple drive is facilitated.
The problem is thereby solved in that the shells are arranged immediately on the roller bearing and that a belt drive is used for the drive with at least one belt provided running directly on the surface of the shells.
With the arrangement of the invention, because the roller bearings directly receive the shells, the tolerances for the rotating shells and also for the adjustment of the wedge slot can be maintained very small. Through the direct drive of the belt engaging at the coating surface of the shells, it is avoided that one needs a special driving shaft or the like, further leading to a simplification. Because the circumferential velocity of the shells is relatively small, the belt speed is also relatively small. Because the belt furthermore runs at a larger diameter it can function with relatively smaller belt tension so that also a relatively smaller belt can be installed.
In practical embodiments of the invention it is provided that the shells exhibit a cylindrical pipe formed shape. Thereby it is possible to form all of the roller bearings with the same dimensions, something that is especially cost effective for series production and for the holding of the bearing in use.
In practical embodiments of the invention it is provided that the shells are carried by axles which protrude beyond both of the end faces of the shell and which are carried at a common bearing housing. Through the common bearing housing it is possible to adjust the axles of the shells, and therewith also the shells, exactly with respect to one another without causing difficulties during the assembly.
In a first embodiment of the invention it is provided that the axles are clamped in shell shaped receptacles of the bearing housing. The shell shaped receptacles in the bearing housing can be prepared in a common manufacturing procedure so that the desired manufacturing accuracies are achieved with simple means.
In another embodiment of the invention, a bearing housing is provided which essentially extends over the axial length of the shells and includes a cover type holder arranged with receptacles for the axles at the end face portions of the shells. It is especially advantageous if the receptacles of the holder are adjustable in distance from one another in the direction of the common plane of the axles. Thereby it is possible to adjust during the assembly, and in any event also later, the size of the desired wedge slot.
In further developments of the inveniton it is provided that the axle of at least one of the rollers, whose shell in the region between the roller bearings is perforated, is constructed hollow and is connecte at a suction connection, and that the axle exhibits a slot formed opening facing the wedge slot. Through this arrangement it is achieved that one or also both rollers can be formed as so called suction rollers whereby also here the manufacturing expenditure is small. It is especially simple if the apparatus is formed with hollow axles made out of a continuous pipe with the same diameter.